If you ever wondered, how to download all of your Personal Documents stored in Amazon (Send to Kindle), just enter https://www.amazon.com/clouddrive/ and jump to „My Send-to-Kindle Docs” directory. Then, select all with the top left corner checkmark icon, and click download. Now, you can just import whole .zip into Calibre.

If you experience problems with communicating (sending AT commands) over serial ESP8266 after upgrade, e.g. – no output, – ERROR in communication, – no input (invalid baudrate), it is just problem with CR LF and not selecting 9600 baud rate, here is possible solution…